Water and other beverages are often supplied in plastic bottles similar to bottle 100 shown in FIG. 1. Bottle 100 includes a main body 101 and a cap 102 that can be unscrewed from main body 101 to open bottle 100. Cap 102 can also be screwed back onto main body 101 to close bottle 100, for example to preserve remaining liquid in bottle 100 after some of the bottle contents have been consumed. Main body 101 may be made, for example, of a plastic such as polyethylene terephthalate (PET), and may be recyclable.
FIG. 2 shows a more detailed view of the upper portion of bottle 100 after cap 102 has been unscrewed from main body 101 via threads 201, exposing spout 202 through which a user can drink or pour liquid. In this kind of bottle, cap 102 is completely detachable from main body 101. Once detached, cap 102 may be easily dropped, lost, or misplaced, resulting in inconvenience for the user of bottle 101 and increasing the risk of spillage.